Improvement in capping piano-hammers



I. BULLARD.

Capping Piano-Hammers.

No.138,001. PatentedApril22,1873.

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r A M P110717 '1. I TH 0 GRAPHIC 00. IV. X USBORNEIS PIVOLESS) UNITED STATES PATENT OFFICE.

ISAAC BULLARD, OF READVILLE, ASSIGNOR OF ONE-HALF HIS RIGHT TO JOHN B. WARREN, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT lN CAPPING PlANO-HAMMERS.

Specification forming part of Letters Patent No. 138,001, dated April 23, 1873; application filed February 8, 1873.

To all whom it may concern:

Be it known that I, ISAAC BULLARD, of Iteadville, town of Hyde Park, in the county of Norfolk and State of Massachusetts, have invented a new and useful Method of Oappin g Piano-Forte Hammers, of which the following is a specification:

Piano-forte hammers are composed of felt pressed on and secured to a wooden head. The object of capping is to prevent the felt from being cut when the hammers come in contact with the string.

The method of capping hammers in common practice is, first, to size the outer surface of the felt with glue to within a quarter of an inch (more or less) of the top or center of the hammer on each side, according to the size of the hammer; then, after the sizing has become sufficiently hard, put on glue and draw or stretch on the leather, which has been previously cut in pieces of the required size, cans ing it to adhere to the hammer except on the top.

The following are the principal objections to capping by the above method: The glue cannot extend to the top of the hammer, for the reason that it makes the felt too hard, destroyin g its elasticity and thereby injuring the tone of the instrument. The constant action against the string causes the leather to stretch and become loose where it is not glued to the felt, and the tone becomes bad, making it necessary to recap the hammers. In consequence of the cap not being glued to the top of the hammer the corners have to be cut away quite beveling to make room for the cap and surface to attach it firmly to the felt. The cutting away of the hammer is considered injurious to the tone by those conversant with the business.

To obviate the abovenamed objections and imperfections caused by securing the cap of the hammer with glue is the object of my invention, which consists in the use of an elastic cement, made of rubber dissolved in benzinc or any other suitable solvent, for attaching the leather to the felt. This cement, be ing elastic, admits of the cap being attached to the whole surface of the hammer, and ob: viates the necessity of cutting away the ham Iner to such a degree as when the cap is at tached with glue.

The tone by this method is very much improved, and retains its purity and power much longer than when the caps are attached with glue.

In putting on the leather in the ordinary way, by glue, it is stretched on very tight, for the reason that there is no glue on the top of the hammer, and the stretching so hardens the leather that it is necessary to voice the piano by pricking up and softening the -caps and hammers'with needles secured in a handle for that purpose; whereas, when the elastic cement is used to attach the leather it is put on nearly in its natural state, by which the desired tone is produced without voicing. It also obviates the difficulty caused by the leather becoming loose, and the tone of the instrument continues perfect for a greater length of time.

Felt sometimes is used for capping, and may be put on with the same kind of cement in the same way.

In the drawing, Figure 1 shows a side elevat-ion of a piano-hammer embracing my invention. Fig. 2 is an edge view of the same, and Figs. 3 and 4; are illustrations of the ordinary hammer as heretofore constructed.

A is hammer head or stock, of wood. B is the foundation felt, secured directly to the wood. 0 is the thick felt, forming the body of the hammer, and D is the leather covering; and, as shown in Fig. 1, it will be seen that the leather is much shorter than in Fig. 3, for the reason that its whole surface is secured to the hammer, while in the old hammer, as illus trated in Fig. 3, the leather cannot be secured to the hammer between I) and c for the reasons hereinbefore stated; and in order to secure the leather firmly to the hammer it is necessary' to make the leather of such a length as to extend down to the wooden stock, and is secured to the felt from a to b and from c to d.

What I claim, and desire to secure by Letters Patent, is-- The method of attaching the caps to piano forte hammers by means of an elastic cement, substantially as described.

ISAAC BULLABD.

Witnesses GARDNER WARREN, F. J. TUTTLE. 

